Human beings have an internal clock which contect us to the exterior. Adaquate sleeping during night hours beeing active during daytime is the evidence for a healty and adecuate rhytm.

Each person has its individual circadian rhytm controlled by our biological clock.

For better understanding our internal clock we have to remember that the evolution of human beeings have been taken place under dark – light cylce.

However nowadays we spend 90% of our time insite of buildings . It makes a difference between the natural outdoor light and the electrical indoor light in terms of intensity , color , direccion of light.

In this way electric light should have the adequate caracatistics that biological rhytm is sycronized and our organism works properly.

Consequences of an uncorrect lighting

  • Without sycronisation to the exterior we have feelings of jetlag.
  • Discontinued night sleep.
  • Hormonal alteration.
  • Alteraciones in state of mind, health and wellbeing.
  • SAD (Seasonal Affective Disorder).

Low light levels over the course of the day

Luz durante la noche

Too much light during the night

How is our circadian system activated

As light could have profound impacts in human health it´s important that lighting designers are aware about the day / night cycles.

The eye works as light receptor – our brain processes the information producing effects as follows:

  • Visual , via reflection of the cortex.
  • Non Visual via hipotálamo – enters the eye directly. Melatopic light has its peak wavelength between 460 and 480 nm ( blue ) informs our circadian system affecting our neuroconductual system.
Circadian cycle


The benefits of simlated daylight

LLedó HCL solutions are based on LED tecnology combined with advanced control systems for the right light in each moment improving visual, cognitive and psychological capacities.

Lledó developed 3 quality solutions with the target to improve the mood and wealth of people. For our tasks we need adequate light in the right place and moment.


  • Changing of the light spectrum over the course of the day.
  • Activation and adaption of the circadian cycle.
  • Colour rendering index above 80.
  • High energy efficiency.


  • Changing of the light spectrum over the course of the day.
  • Activation and adaption of the circadian cycle.
  • Colour rendering index above 90 and R9 ( CRI for red ) above 50.
  • Enhanced visual acuity.


  • Changing of the light spectrum over the course of the day.
  • Continous activation of the circadian cycle augmentend circadian eficiency.
  • Colour rendering index above 95 and 70 for R9 (red values).
  • Enhanced visual acuity.
  • Spectral radiation similar to native daylight.

Parameters of circadian light

It is necessary that 240 MDEI ( Melatopic Daylight Equivalent Iluminance ) reach to our eyes for syncronisation and activation.
from a light source D65 or similar light quantity.

LLEDÓ HCL solutions go far beyound basic colour temperature changings – its about spectral changings, appropiated wavelenghts for the adaption to biological rhytms.
We offer solutions which reproduces the beneficial efects of daylight .

Métrica luz circadiana

Smel (460-480nm)
Vision (570nm)
Red light is visible via IpRCC

LLEDÓ HCL Solutions


2 Surfaces – only one mircoprismatic component.

  • Uniformity over 3 m interdistances.
  • High visual Confort.
  • UGR 19 up to 3500lm, 30W and 117lm/w.


  • Redesign to increase visual comfort up to UGR18 4,550lm 39W and 117 lm/W Metallic up to UGR19 2,600lm 23W and 113lm/W White.
  • Reflectors with different finishes for integration in any space.

Nobel price in fisiology / medicine 2017

Te Jeffrey C Hall, Michael Rosbash and Michael W Young where granted the price in 2017 for discovering the molecular mecanics which controls the circadian rhym.

The mecanics affects the segregation of diferent hormons we need for diferent phases during the course of the day.

Premio Nobel

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